I have a 2014 300C with 8 speed transmission and V6 engine. It doesn't seem to shift properly when using cruise control. For example, I can drive 50 to 55 MPH without cruise and the transmission shifts up fine, with the engine running at low revs. When I engage the cruise control, the car downshifts and the revs jump a couple of hundred RPM. It will never upshift completely with the cruise on. Is this normal for these cars? Dealer was no help on this. Has anyone else seen this happen?